A moral imperative is a principle originating inside a person's mind that compels that person to act. It is a kind of categorical imperative, as defined by Immanuel Kant. Kant took the imperative to be a dictate of pure reason, in its practical aspect. Not following the moral law was seen to be self-defeating and thus contrary to reason. Later thinkers took the imperative to originate in conscience, as the divine voice speaking through the human spirit. The dictates of conscience are simply right and often resist further justification. Looked at another way, the experience of conscience is the basic experience of encountering the right.
An example of not following a moral imperative is making a promise that you do not intend to keep in order to get something.
Toby Ord Explores a moral imperative in relation to economics and global health. A hypothetical example he gives is that a group has $40,000 dollars to spend on blindness. The money could be spent to provide one U.S. person with a seeing eye dog and training or could be used to reverse the effects of 2,000 cases of trachoma in Africa through surgery. The cost-effective answer would be to help more people.